Digital images gathered from digital cameras are susceptible to alterations and modifications, making the digital images appear to display elements that were not present during the taking of the photograph. Many programs capable of alter digital images are readily available to anyone. Thus digital images can be altered at any time after initial generation.
Moreover, even if the digital image is retrieved directly from the digital camera storage, one cannot be sure that the image had not been previously overwritten by an altered version since conventional digital camera storage is designed to be bi-directionally accessible by a computer, for example.
Because digital images are so easily alterable, issues arise when authenticating digital images, such as for introduction as evidence in a criminal or civil trial. In order to show that a digital image is unaltered, a strict chain of custody must be proven, with one gap in the chain proving fatal to the introduction and acceptance of the digital image into evidence. Not only does the chain have to be shown for possession of the image from the moment of image creation until the time of introduction as evidence, it must also be shown that the file has remained unaltered for that length of time. Since the chain of custody needs to be proven for each digital image relied upon, the process can be onerous and potentially problematic if the chain of custody has even the briefest of gaps.
As a result, in many instances, film photography is also used so that the film images will be admissible into evidence. Film images are more readily admissible into evidence because film images recorded on a film negative are difficult to alter in contrast to digital photographic images. However, using both film and digital photographic image recording is both time and resource consuming.
As one example, during a typical law enforcement investigation, many digital photographs are taken of a scene, objects, etc. These digital photographs are gathered and stored on conventional digital cameras, typically on conventional storage mediums, such as CompactFlash®, or Secure Digital (SD) storage mediums. These digital images may be used by law enforcement for their own in-house procedures, while a second set of similar, nearly exact, set of film images are gathered. The digital images are typically used during the investigatory stage because they are more easily transferrable and can be enhanced and enlarged with ease. In the meantime, the set of film images is stored and will be relied upon in the future if they are needed at a trial.
To date, there is no digital image storage medium available in the marketplace that prevents alteration of digital images stored thereon. Therefore, digital images still face admissibility issues in court proceedings.
Embodiments of the present application provide methods and devices that address the above and other issues.